Process for protecting a substrate with an n{11 -pyrazylaminoarylsulfonamide intumescent agent

ABSTRACT

Intumescent compositions of the invention comprise certain N4pyrazylaminoarylsulfonamides, such as N4-2-pyrazylsulfanilamide and derivatives thereof. The intumescent agents may be employed in conjunction with additives conventionally used in intumescent compositions. For use in protecting substrates from heat and fire, the intumescent compositions may be applied to the substrate in any suitable manner, such as by electrodeposition, spraying onto an adhesive substrate, or application of a coating composition comprising the intumescent agent.

lii iw 1 Nov. 27, 1973 [s41 PROCESS FOR rag'i riii g T R 3 SUBSTRATE WITHAN N HRAZYLAMINOARYLSULFONAMIDE--M-v I i Northey,'Sulfonamides,'pp. 45, 115-117, (1948).

INTUMESCENT AGENT [75] inventor: Shirley H. Roth, Highland Park, NJ.

Assignee:

Filed: Feb. 28, 1972 Appl. No.: 230,136

' U.S. Cl. 117/136, 106/15 FP Cities Service Company, New York,

- certain N-pyrazylaminoarylsulfonamides, N-2-pyrazylsulfanilamide and derivatives thereof. The

NG XR,

3,7o7,554 12/1972 Hardy in/136x omen PUBLICATIONS Primary Examiner-Wiiliam D. Martin Assistant Examiner-Harry .l. Gwinnell Attorney-Richard S. Strickler et al.

ABSTRACT lntumescent compositions of the invention comprise such as 51 int. Cl. C09d s/1s,co91 3/28 f agents be employed) Fonjmcfiofl -[58] Field of Search 117/136; 252/8.l; addmves convemlonally used m mwmescem V 106/15 260/2399 compositions. For use in protecting substrates from heat and fire, the intumescent compositions may be [56] References Cited applied to the substrate in any suitable manner, such UNTED STATES PATENTS as by electrodeposition, spraying onto an adhesive 4 D substrate, or application of a coating composition 5,222,???) loflgg wreugly et a1. 12167242332): comprising the intumescem agent. 3,663,464 5/1972 Sawko 117/136 X 5 Claims, No Drawings i) 1* Lam J f"? z 1 PROTECTING A SUBSTRATE I WI H AN N 09-PYRAZYLAMINOARYLSULFONAMIDE INTUMESCENT AGENT BACKGROUND OF THE INvENTIoN PROCESS F OR 1. Fielcl of the Invention This invention relates to intumescent compositions and more particularly relates to such compositions containing a one-component intumescent agent.

2. Description of the Prior Art I It is known that a substrate may be protected from are also utilizable. When R is a substituted pyrazyl radical, the nitrogen of the ar-amino group may be attached directly to the pyrazine ring, or it may be attached to the pyrazine ring through the substituent.

-- As indicated above, R may be hydrogen or a hydro- 3 carbon, substituted hydrocarbon, or acyl radical, pref- I I erablyv hydrogen or a C,-C alkyl, phenyl, amino- I phenyl, sulfonamidophenyl, nitrophenyl, or acetyl radii cal.

heat and fire by the application of an intumescent com- I position. intumescent compositions of the prior art usually contain an intumescent agent having at least'three- SUMMARY OFTHE INVENTION An object of this invention is to provide a novel class I of one-component intumescent agents.

Another object is to provide such intumescent agents 9 ethylbenzenesulfonamide,

are N-2-pyrazylsulfanilamide, 4-( Z-pyrazyl )-amino-3- chlorobenzenesulfonamide, 2-( Z-pyrazyl )amino-4- bromobenzenesulfonamide, 4-( Z-pyrazyl )amino-2- 3-( Z-pyrazyl )amino-4- 4- 2- 4-( 2- chloromethylbenzenesulfonamide, I pyrazyl )amino-Z-butoxybenzenesulfonamide,

pyrazyl)amino-3-chloromethoxybenzenesulfonamide,

4-( Z-pyrazyl )amino-3-hydroxybenzenesulfonamide,

' 4-(2-pyrazyl)amino-3 -carboxybenzenesulfonamide,

'- (5-chloro-2-pyrazyl )sulfanila'mide,

having good efficiency and a low level of moisture sensitivity. 1

These and other objects are attained by using as intumescent agents compounds corresponding to the formula: v

wherein Ar is a divalent aromatic residue, R is a pyrazyl or substituted pyrazyl radical, and R is hydrogen, hydrocarbon, substituted hydrocarbon, or acyl.

DESCRIPTION OF THE PREFERR D EMBODIMENTS The intumescent agents of the invention may be any compounds corresponding to the above formula. However, they are preferably compounds wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative thereof. When the aromatic ring bears organic substituents, it is usually preferred-that these substituents contain one to five carbon atoms. When there are halo substituents, it is usually preferred thatthey be chloro or bromo. It is also preferred that the aromatic ring have at least one free reactive position.

R of the above formula is preferably apyrazyl radi- 4-(Z-pyrazyl)-amino-3-aminobenzenesulfonamide, 4- (2-pyrazyl)amino-2 acetamidobenzenesulfonamide,

2-(2-pyrazyl)amino-4-nitrobenzenesulfonamide, N- I N-(5-bromo-6- methyl-2-pyrazyl)sulfanilamide, N-(5-carboxy-2- pyrazyl)sulfanilamide, N-(5-hydroxy-2-pyrazyl)- sulfanilamide, N -(2-amino-5-pyrazyl)sulfanilamide, N-(2-ethylthio-5-pyrazyl)sulfanilamide, N-(6- sulfonamido-Z-pyrazyl)sulfanilamide, N-(5-methyl-2- pyrazyl)sulfanilamide, N-(2-methoxy-5- pyrazyl)sulfanilamide, N-(5-phenyl-2- pyrazyl)sulfanilamide, N-2-benzopyrazylsulfanilamide, N-ethyl-N-2 pyrazylsulfanilamide, N-(4- aminophenyl)-N-2-pyrazylsulfanilamide, N'-(4- sulfonamidophenyl )-N"-2-pyra.zylsulfanilamide, N'-(4- nitrophenyl)-N-2-pyrazyl-sulfanilamide, N-acetyl-N- Z-pyrazylsulfanilamide, the corresponding naphthalene compounds, etc. When not readily available, these I compounds may be prepared by known techniques.

cal, but it may hear one or more substituents if desired.

For use in protecting a substrate from heat and fire, j

the intumescent agents of the invention may be applied in-any suitable manner, e.g., electrodeposition, spraying of powdered intumescent agent onto an adhesive substrate, etc. However, it is usually preferred to compound the intumescent agent with a binder, e.g., nitrocellulose, and optionally also with one or more of the other ingredients conventionally used in intumescent compositions, e.'g.', stabilizers, dispersing agents, .pigments, driers, biocides, anti-foamers, thickeners, protective colloids, fillers, blowing agents, etc.; disperse coating compositions, it is frequently convenient to apply these coating compositions in the form of a paint having a solids content of about 10-70% by weight and an intumescent agent/binderweight ratio of about 0.075-14/1 to deposit a coating having a dry thickness of about 0.00l-0.75 inch.

The intumescent agents of the invention are efficient,

have low moisture sensitivity, and intumesce to form foams having good volume, cell structure, and adherence to substrates, such as wood, metal, and plastics. They are also useful as flame retardants in normally flammable compositions.

The following example is given to illustrate the invention and is not intended as a limitation thereof.

Exemplary of the intumescent agents of theinvention i EXAMPLE I Place one gram of N-2-pyrazylsulfanilamide in an 7 1 aluminum pan and flame it with a propane torch. The

compound intumesces to form an excellent volume of foam having a good cell structure.

Similar results are also observed when the other intu-, mescent agents mentioned in the specification'are substituted for the intumescent agent of the Example. 10

' wherein Ar is adivalent aromatic residue,R is a pyrazyl or substituted pyrazyl radical, and R is hydrogen, hy-

o 'nHN-Ar-lL-Nnw drocarbon, substituted hydrocarbon, or acyl.

I 2. The process of claim 1 wherein Ar is a divalent aromatic'residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative'thereof.

3. The process of claim 1 wherein R is a pyrazyl radi-- cal.

4. The process of claim 1 wherein R are hydrogen. 5. The. process of claim 1 wherein the intumescent agent is N-2-pyrazylsulfanilamide. F t 

2. The process of claim 1 wherein Ar is a divalent aromatic residue derived from benzene or naphthalene or an alkyl, haloalkyl, alkoxy, haloalkoxy, halo, hydroxy, carboxy, amino, amido, or nitro derivative thereof.
 3. The process of claim 1 wherein R is a pyrazyl radical.
 4. The process of claim 1 wherein R'' are hydrogen.
 5. The process of claim 1 wherein the intumescent agent is N4-2-pyrazylsulfanilamide. 